Special Issue "Biocides"

Guest Editor
Prof. Dr. Joseph Oliver Falkinham
Department of Biology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
Website: http://www.biology.vt.edu/faculty/falkinham/
E-Mail:

Dear Colleagues,

Biocides and disinfectants are widely employed throughout the world and used in a variety of applications including hand sanitization, surface disinfection in food preparation, surface sterilization in hospitals, and the disinfection of a variety of solutions that are used in industry (e.g., metal-recovery fluids). As has been the case with antibiotics, biocide resistance is increasing, and threatens to reduce the applicability of biocides to control contamination. The proposed, open-source, special issue will bring together all current knowledge of biocides and will provide unprecedented access.

It is anticipated that the following topics will be included in the special issue:

• Mechanisms of biocide action
• Mechanisms of biocide resistance
• Measurement of biocide susceptibility
• Identification of biocide targets
• Selection for biocide resistance
• Interaction between biocides
• Effect of growth conditions on biocide susceptibility

Prof. Dr. Joseph Oliver Falkinham
Guest Editor

Related Conferences

International Conference on Antimicrobial Research (ICAR2010), Valladolid (Spain), 3-5 November 2010

Submission

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. Papers will be published continuously (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are refereed through a peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. International Journal of Molecular Sciences is an international peer-reviewed Open Access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1400 CHF (Swiss Francs).

• biocides
• disinfectants
• antiseptics
• surfactants
• antimicrobial agents
• targets
• resistance
• sensitivity
• interaction
• synergism
• antagonism

Type of Paper: Review
Title: Bacteriocins as Antimicrobial Agents
Author: Darja Zgur-Bertok
Affiliation: Department of Biology, Biotechnical Faculty, University of Ljubljana, Vecna pot 111, 1000 Ljubljana, Slovenia; E-Mail: darja.zgur@bf.uni-lj.si
Abstract: Antibiotic resistance of bacterial pathogens is an increasing global threat to public health care. To prevent selection and dissemination of resistance the use of traditional antibiotics must be limited, while to battle bacterial pathogens, including multiresistant strains, alternative effective therapies must be sought. All major lineages of Bacteria as well as some Archeae produce bacteriocins, ribosomally synthesized proteinaceous substances. While bacteriocins have been shown to promote microbial diversity and genetic diversity, they also exhibit great potential as antimicrobial agents. Bacteriocins in contrast to antibiotics, generally exhibit a narrow killing spectrum acting against specific pathogens and not affecting the normal microflora. This review, commencing with an introduction of the structure, mechanism of bacteriocin action and role of bacteriocins in natural settings, focuses on efforts to use bacteriocins and bacteriocin producing strains as antimicrobial agents. Resistance against bacteriocins will also be discussed.

Title: Cellulose Biosynthesis Inhibitors: Comparative Effect on Bean Cell Cultures
Authors: Penélope García-Angulo, Ana Alonso-Simón, Antonio Encina, Jesús M. Álvarez and José L. Acebes
Affiliation: Área de Fisiología Vegetal, Facultad de C.C., Biológicas y Ambientales, Universidad de León, 24071 León, Spain; E-Mail: jl.acebes@unileon.es (J.L.A); penelope.garcia@unileon.es (P.G.A.)
Abstract: In the last years several compounds have been reported to inhibit cellulose biosynthesis in plants, and some of them are used as herbicides. The variety of bioassays developed to evaluate different inhibition responses for each of these inhibitors makes it difficult to compare the results obtained. This work aims i) to test a single inhibitory assay for comparing active concentrations of a set of putative cellulose biosynthesis inhibitors and ii) to characterize their effect on cell wall polysaccharides biosynthesis following a short-term exposure. For the first aim, dose-response curves for dry-weight increase inhibition following a 30 d exposure of bean callus-cultured cells to these inhibitors were obtained. The compound concentration able to 50% inhibit the dry weight increase regarding to control (I₅₀) ranged from subnanomolar (CGA 325´615), to nanomolar (AE F150944, flupoxam, triazofenamide and oxaziclomefone) and micromolar (dichlobenil, quinclorac and compound 1) concentrations. In order to gain a better understanding of the effect of the putative inhibitors on cell wall polysaccharides biosynthesis, the [¹⁴C]glucose incorporation into cell wall fractions was determined after a 20 h exposure of cell suspensions to each inhibitor at their I₅₀ value. All the inhibitors tested decreased glucose incorporation into cellulose with the exception of quinclorac, which increased it. A cluster and PCA analysis based on [¹⁴C]glucose partitioning into the cell wall components identified three groups of compounds. The first group included quinclorac, which increased glucose incorporation into cellulose; the second group consisted of compound 1, CGA 325´615, oxaziclomefone and AE F150944, which decreased glucose incorporation into cellulose but increased it into tightly bound cellulose fractions; and the third group, comprising flupoxam, triazofenamide and dichlobenil, decreased glucose incorporation into cellulose and increased it into a pectin rich fraction. These results show that cellulose biosynthesis inhibitors form a heterogeneous group with different inhibition parameters and range of active concentrations, which may affect the cell wall in different ways depending on whether the exposure period is short (20 h) or  long (30 d). These inhibitors can be clustered into several subgroups according to the modifications induced in cell walls, indicating different modes of action with several targets in the cellulose biosynthesis process.

Type of Paper: Article
Title: Sub-MIC levels of the Disinfectant Benzalkonium Chloride Select for a Tolerant Subpopulation of Escherichia coli with Inheritable Characteristics
Author: Birgitte Moen
Affiliation: Nofima Mat, N-1430 As, Norway; E-Mail: birgitte.moen@nofima.no
Abstract: Exposure of Escherichia coli to sub-MIC levels of benzalkonium chloride (BC), an antimicrobial membrane-active agent commonly used in medical and food-processing environments, resulted in major cell death and changes in cell morphology (filamentation). A small subpopulation (1-5% of the initial population) survived and regained similar growth rate as non-stressed cells. These survivors maintained tolerance to BC after serial transfers in medium without BC. To withstand BC during growth the cells up regulated the acrB gene (member of the AcrAB-TolC efflux system) and regulated outer membrane porin genes (ompFW) and several genes (hdeA, htrA (degP), osmB, pflB, rpoS, ybdQ (uspG) and yfiD) involved in protecting the cell from the osmotic- and oxidative stress. Cells pre-exposed to osmotic- and oxidative stress (sodium chloride, salicylic acid and methyl viologen) showed higher tolerance to BC. Genome sequencing of a control and two isolates selected after growth in sub-MIC levels of BC revealed a point mutation in gene rpsA (Ribosomal protein S1) in one of the isolates.  The results indicate that there are several different mechanisms responsible for the observed tolerance to sub-MIC levels of BC in E. coli and that the maintained tolerance can not solely be explained by the observed point mutation.
Keywords: Escherichia coli; quaternary ammonium compounds; benzalkonium chloride; selection of subpopulation; efflux pump; osmotic- and oxidative stress response